Java – key value storage recommendations

I need a very basic key value stored as Java I started to use HashMap, but it seems that some space in HashMap is invalid (I am storing about 20 million records, and it seems that ~ 6GB ram is required)

The mapping is map < integer, string >, etc., so I am considering using GNU trove tintobjecthashmap < byte [] >, and storing the mapping value as ASCII byte array instead of string

As an alternative, is there a key value store that only needs to add jar files, does not immediately save the entire map in RAM, and is still quite fast?

Solution

Using Berkeley DB

This will definitely bring you great memory and speed without increasing the complexity of your application Please enjoy!